He is the most patient man I know. Jim Leavelle, the retired Dallas police detective who was handcuffed to Lee Harvey Oswald the moment Oswald was fatally shot, answers every question about those dark days in November 1963 as if he were hearing them for the first time.

Forty-five years later, Leavelle still wears a replica of the famed Resistol hat at public events when he is asked to talk about history. He is 88 now, retired in Garland, an old-school gentleman who still looks much the same as he did in that legendary photograph of Oswald crumpling to the floor while tethered to him.

Leavelle is always patient with history buffs, but he’s not so patient with his credit card company. A couple of months back, after he had canceled a cookbook he supposedly ordered, American Express kept billing him. He grew so angry that he cut his card into pieces and mailed them to the company.

With that, the owner of one of the most famous faces in American history thought he was through with AmEx. Maybe so, but the company wasn’t done with him.

The bills kept coming for Food and Wine Cookbook, which Leavelle doesn’t remember ordering. Even if he did, he says, he canceled within the allotted time. He was told that everything would get squared away. He’d get a credit on his bill. He never did.

He called again. Same line.

The bills kept coming, and he threw them away. Eventually, his original disputed $35 charge ballooned with interest and penalties to $114.

Soon a collection agency started pestering him. He ignored it, too. That’s when I heard about it.

Admittedly, an 88-year-old man doesn’t need to worry too much about his credit score, which drops when a delinquency, even an inaccurate one, is charged. But surely he doesn’t need the pestering. Especially this guy, who has been pestered his entire adult life because one day, a long time ago, he found himself in the worst place at the worst time.

An American Express spokeswoman confirmed that Leavelle had properly tried to cancel the cookbook and asked for the refund. But the refund request, which was approved, never went through, the spokeswoman said, because a third-party vendor sells the books.

“He’s correct,” spokeswoman Marina Hoffmann said. “He canceled us. He wanted it refunded. Obviously, looking at it, it was very clear that the customer was not at fault.”

Yet nothing he tried worked. Then Leavelle was so agitated that he pushed it aside, even though he was in the right.

I asked Hoffmann what a customer is supposed to do.

“Just be persistent,”Hoffmann said.”I realize he spoke to three different people. It’s kind of a lesson for your readers. To be vigilant and make sure that customer service follows through with what they promise you.”

See, everybody? It’s our fault now.

Leavelle’s credit report was cleared of the supposed delinquency. His credit card, though, is in pieces and long gone.

Don’t give up when a company is sending you bills that are unfair or inaccurate.

When buying through a credit card company that works with a third-party vendor, cancel with both the credit card company and the vendor, if possible.

After canceling, check your free annual credit report to verify that the cancellation didn’t mar your record. Get one free credit report every year at www.annualcreditreport.com.